A partial shutdown of federal government operations appeared nearly certain Friday as President Barack Obama and congressional leaders failed to clinch a deal on a plan to curb spending for the rest of the fiscal year, which ends on Sept. 30.

It would be the first such shutdown since 1996.

"We're very hopeful that we can reach an agreement on the budget today," Majority Leader Harry Reid said on the Senate floor Friday morning.

But he said an accord was being blocked by the insistence of many Republicans on defunding a program called Title X which pays for contraceptives, breast and cervical cancer screening, and testing for sexually transmitted diseases for low-income Americans.

The spending bill the House passed in February specifically prohibits any funding for Planned Parenthood and it affiliates. Planned Parenthood receives about $70 million in annual funds under Title X, about a quarter of all Title X funding.

But House Speaker John Boehner contradicted Reid, saying, “There is only one reason that we do not have an agreement as yet and that issue is spending."

Here's a guide to spending squabble and the impending shutdown — submit your own questions at the bottom of this page.

Why would a government shutdown be only partial and not complete?
According to the Office of Management and Budget memo which regulates shutdowns, the federal employees kept on the job during a shutdown include those who “are engaged in military, law enforcement, or direct provision of health care activities” and those who are necessary “to protect life and property.”

According to a 1981 OMB memo, among those continuing to work despite a shutdown: federal workers in charge of “safe use of food and drugs and safe use of hazardous materials” and many other job categories such as border patrol officers, air traffic controllers, airport security screeners, and those in charge of federal prisoners.

Barry Anderson, who served as assistant OMB director for budget matters during the last government shutdown in 1995 and 1996, said, for example, that a national park doesn’t fall into any of the categories named by the OMB memo, but the guards protecting national parks from vandals and thieves would fit under the rubric of “protect life and property” so they’d stay on the job.

A reader asks, “We have campground reservations in two weeks at Zion National Park in Utah for spring break. Will we get a refund?”

A spokeswoman for Zion National Park said people with reservations will be given refunds if the park closes due to a shutdown.

All 394 units in the National Park system will be closed in the event of a shutdown. That includes not only parks, but historic battlefields such as Chickamauga and Gettysburg, and other sites administered by the National Park Service.

The Park Service will refund the fees that campers pay for using campsites in NPS units.

If a person has paid an entrance fee at a national park and then is required to leave the park due to a government shutdown, the Park Service will allow that entrance fee to be honored at a later date once the park re-opens, if the person shows a receipt proving that he'd already paid the entrance fee.

At some NPS sites, concessionaires or outside contractors run the lodges and other facilities. Each individual concessionaire at each of the national park units will address the question of refunds.

Guests who are already staying at one of the lodges within a national park will be given 48 hours to vacate the premises once a shutdown starts.

How would funerals at Arlington National Cemetery be affected by a shutdown?
On its website, Arlington National Cemetery says it "will continue to conduct interment services as scheduled the week of April, therefore, the cemetery will be open to the public.”

If I'm getting Social Security benefits, will I still get them in the event of a partial government shutdown?
Social Security Commissioner Michael Astrue said that Social Security payments would continue, and applications for benefits would continue to be processed, though some services would be limited.

Would elderly people on Medicare still have their medical bills paid if there were a government shutdown?
Yes.

Let’s take the case of an 80-year old man getting weekly treatments from his doctor. “Clearly the payments to the doctor for this man’s treatment are not affected,” Anderson said.

However he added that the operations of the Centers for Medicare and Medicaid Services, the agency that runs Medicare, are funded by annual appropriations.

The CMS might have contracted out some of the task of reimbursement of doctors in this fiscal year to private-sector contractors. “If that’s the case, not only will the man get the treatment and not only will there be money for that treatment, but the money will actually be paid,” said Anderson.

However if CMS employees are directly handling reimbursement of the doctor in this man’s case, then payment will likely be slowed down by a government shutdown. “The doctor will get the money, but he won’t get the money promptly. He will only get it after the CMS people are back at work,” Anderson said.

How about Americans serving in the Army, Navy or the other military services — will they get paid if there's a shutdown?
Their pay would be interrupted — they’d have to wait to collect their pay until Congress and the president agreed to a spending bill.

What about people who are getting unemployment insurance benefits?Unemployment insurance is funded jointly by the state and the federal governments and benefits would not be affected by a short-term federal shutdown.

In Colorado, people getting unemployment benefits will continue to receive them even in the event of a federal government shutdown, said Cher Haavind, a spokeswoman for the Colorado Department of Labor & Employment. She said the 54,000 federal employees working in Colorado may also be eligible for unemployment insurance if they are furloughed for more than a week.

What about mail delivery?
According to NBC News correspondent John Yang, the Postal Service doesn't use federal funds for mail delivery so it will not be affected.

Would the food in local grocery stores be affected by a government shutdown?
No. Since federal inspection of meat, poultry, eggs and grain comes under the heading of food safety, it would continue during a government shutdown.

If I'm planning travel overseas, can I still get a passport?
Applications for new and renewed passports and visas would halt during a shutdown.

If a shutdown went beyond the April 18 tax filing deadline, would taxpayers still need to file their income tax returns by that date?
Yes. The filing deadline remains the same, April 18. If the government shuts down, Commissioner of Internal Revenue Douglas Shulman said Wednesday, his agency will not process tax returns filed on paper, but will process those filed electronically.

Will the U.S. Treasury run out of funds to spend on Friday?
No. Withholding from workers’ paychecks and other tax collections, as well investors’ purchases of Treasury securities, supply the government with a year-round flow of funds. According to the most recent Daily Treasury Statement, the government had an operating cash balance of nearly $48 billion on Wednesday.

But the money can’t be spent without congressional authorization. As Article I of the Constitution says, “No Money shall be drawn from the Treasury, but in Consequence of Appropriations made by Law …

Is the impasse over a spending plan for this fiscal year related to the upcoming vote on whether to raise the federal debt limit?
Not directly, no. Even if Obama and congressional Republican leaders reach an accord on spending for the rest of fiscal year 2010, the federal government will still reach its borrowing limit in the next several weeks.

The one common factor in both cases is a dispute over how much money the federal government should borrow, collect through taxation, and spend. Republicans are reluctant to raise the borrowing limit and want to force more spending cuts.

How much money are the Republicans and Democrats in Congress squabbling about?
The starting point for the bargaining was the spending bill the Republican-majority House passed on Feb. 19. Compared to current spending levels, it would cut spending by $61 billion.

The bill cut discretionary spending on agencies such as the Environmental Protection Agency, and the National Park Service. Entitlement spending, including Medicare and Social Security, was spared.

The Democratic-majority Senate rejected that bill. And Obama is reportedly refusing to accept anything greater than a $33 billion reduction in spending.

Measured as a percentage of all federal spending, how large a spending cut is Congress considering?
A $61 billion cut would be equal to 1.6 percent of total projected federal spending in this fiscal year. It’s equivalent to about five or six days’ worth of federal spending.

One reason it's so difficult for Congress to cut even 1.6 percent of federal spending is that spending almost never declines.

With the exception of 2010, when spending fell due to lower outlays for the Troubled Asset Relief Program and payments to Fannie Mae and Freddie Mac, the last time spending fell was in 1965. Only three of the current members of Congress were serving in 1965.

Video: Shutdown would come with big ripple effects

Closed captioning of: Shutdown would come with big ripple effects

>>is a shutdown, how will you be affected.
pete williams
has more on that from the
lincoln memorial
. good morning.

>> reporter: good morning. a shutdown would be most visible at a place like this. a big tourist draw in washington and like all parks and monuments, the
lincoln memorial
would be closed to visitors. filing a paper
tax return
? the irs would stop processing, slowing refunds for paper filers. electronic
tax returns
would be processed, including those due refunds. shut down or not the tax deadline of
april 18
doesn't change. the fha would stop guaranteeing new home loans, a blow to fragile
housing market
.

>>april, may and june are the biggest months of the
housing market
. this is not a time to challenge the mortgages out there.

>> reporter: the government would stop issuing passports except for emergencies and would freeze work on new or renewed ones. the
national parks
would close including fwrangrand canyon and yosemite. this montana woman lives near yellowstone.

>>i want them to settle this budget mess and act like adults and compromise.

>> reporter: some federal work would continue including virtually all
law enforcement
,
coast guard
, fbi, border, immigration and customs agents. tsa screeners would check airline passengers and
air traffic controllers
stay on the job. uniformed members of the military remain on duty around the world but they would not be paid until the shut down ends. a florida wife of a
u.s. marine
said it would be distracting for those in combat.

>>to sit on the front line going, god, i don't care about afghanistan. i wonder if my wife and kids are being fed at home.

>> reporter: veterans administration
would stay open. checks continue flowing to 53 million people who get
social security
payments. same for medicare and medicaid assuming the shutdown doesn't last long. mail delivery would not be affected because the
postal service
generates its own income. half of the federal workforce would be told to stay home and it would be illegal for them to volunteer to come to work. if they did, they could be fired. meredith?